Automatic interlocking electrical connector



Feb. 1, 1966 w. w. DE VORE, JR 3,233,204

AUTOMATIC INTERLOCKING ELECTRICAL CONNECTOR Filed Sept. 17, 1965HI'IURNEYS.

United States Patent 3,233,204 AUTOMATIC INTERLOCKING ELECTRICALCONNECTOR William W. De Vere, Jr., Palos Verdes Estates, Calif.,

assignor to Harvey Hubbell, Incorporated, Bridgeport,

Conn, a corporation of Connecticut Filed Sept. 17, 1963, Ser. No.309,488 Claims. (Cl. 339-45) This invention relates to two-partelectrical cable connectors and, more particularly, to such connectorsof the interlocking type.

Interlocking electrical cable connectors are widelyused wiring deviceswhich usually consist of two parts, a connector body portion and aconnector cap. The body of the connector encloses female electricalcontacts and the cap includes male electrical contact blades whichextend therefrom and are inserted into the female contacts when the capand body are mated. The male blades are somewhat L-shaped so that alaterally projecting lug is formed on each blade. The body of theconnector includes a front wall having slots for receiving the blades.The cap is mated with the body by inserting the contact blades into thecorresponding slots. The contact blades thereupon make electricalconnection with the female contacts within the body. The cap is thenrotated relative to the body and this causes the lug on each of thecontact blades to move into a position out of alignment with itsassociated slot and behind the front wall of the body. This takes placewithout interrupting the electrical connections between contacts of thecap and body, and the connector parts are thereupon locked together sothat they are no longer separable by simply attempting to pull themapart axially. In order to unlock the connector parts, they must berotated in the opposite direction from which they were originallyrotated to lock them, which realigns the blades with the slots so thatthe cap may be separated from the body by .pulling them apart axially.

In the prior art connectors of the type described, a positive rotatingforce must be applied to the connector parts in order to elfect initialinterlocking. In order to eliminate the requirement for manual actuationof the interlocking means, there have been provided in prior art devicesauxiliary means for automatically rotating the cap and body relative toone another during the time they are being mated. However, most of thedevices heretofore proposed have had certain deficiencies. For onething, such devices have been relatively complex and, accordingly, aresomewhat expensive to manufacture. Another drawback of prior artautomatic interlocking connectors is that many of them do not allow formisalignment of the male blades relative to each other, which sometimesoccurs in practice.

Accordingly, it is a primary object of this invention to provide animproved automatic interlocking electrical connector. Other objects areto provide such a connector which is inexpensive to manufacture, whichhas few parts, and which automatically adjusts to the alignment of themale contact blades of the connector cap. Other objects, features, andadvantages of this invention will be more apparent from the followingdescription, the appended claims, and the figures of the attacheddrawing, wherein:

FIG. 1 illustrates in side elevation a two-part electrical connectorembodying the invention in unconnected condition;

FIG. 2 is a sectional view on an enlarged scale of the body of theconnector of FIG. 1 taken substantially along the line 22 of FIG. 1;

FIG. 3 is a sectional view taken substantially along the line 33 of FIG.2, but showing the connector parts during their connection;

FIG. 4 is a transverse sectional view illustrating the operation of theinterlocking means of the connector parts as they are connected;

FIG. 5 is a view similar to FIG. 4 illustrating the interlocking motionof the interlocking means of the connector parts; and

FIG. 6 is an exploded prespective view showing the construction of themajor operating elements of the interlocking means of the connector ofthe invention.

In FIG. 1 there is illustrated a two-part electrical connectorcomprising a connector cap 10' and a connector body 12. The cap and bodyare each provided with a suitable cable clamp 14-14 for mechanicalconnection to electrical cables 1616. The cap 10 is of generallycylindrical shape and from one planar surface there projects a pluralityof male electrical contact line blades 18 and a grounding blade 18'.Each of blades 18, 18' is connected within cap 10 in the usual manner toone of the electrical conductors of the cable 16.

The body 12 is also of generally cylindrical configuration. It includesa cylindrical base 20 of a suitable di electric material. The base 20 issurmounted by a main body portion 22 which is also in the form of acylinder and is secured to base 20 by means of suitable screws 24 whichare threaded into a metallic shell or end plate (not shown) which alsosupports the cable clamp 14. The base 29 and body portion 22 define aplurality of internal compartments therein which enclose. the requiredelectrical female contacts. Main body portion 22 also includes a frontwall 26 having a plurality of arcuate slots 28, each positioned toreceive an individual one of the male contact blades 18, 18. The blades18, 18' are of the interlocking type and are of generally L-shapedconstruction, having a laterally projecting lug 3% which defines aninwardly facing shoulder 32. The shoulder 32 is designed to engage theinner surface of front wall 26 and interlock the cap 10 and body 12.

Projecting inwardly from the front wall 26 of main body portion 22 is araised boss 34 (FIG. 3) which has a square opening 35 axiallytherethrough from the outer surface of front wall 26. Circularlyarranged around this boss and mechanically supported by base 20 are aplurality of U-shaped electrical female spring contacts 36. Contacts 36are positioned in the usual fashion slightly radially offset from thecenter lines of corresponding slots 23 to receive the male contactblades 18, 18' after they are inserted into the slots and to maintainelectrical contact when the cap 10 is rotated clockwise, relative to itsdirection of advancement toward body 12. A square retaining shaft 38 iscontained within the square opening 35 in boss 34. Shaft 38 includes anenlarged cylindrical head 46 at one end and a rounded threaded portion40 at its other end which is designed to threadedly engage a nut 42disposed in a suitable counter-sunk opening 44 in front wall 26.

The interlocking means actuating mechanism of this invention ispositioned around the retaining shaft 38 between its head 46 and theflat surface 47 of boss 34. This mechanism consists of a rigid .plasticmaterial lower drive arm 48 and a rigid plastic material upper drive arm50, separated from one another by means of a metallic spacer 52. Thelower drive arm 48 comprises a central ring portion 54 having a circularopening of larger diameter than the diagonal dimension of the retainingshaft 38. Ring portion 54 carries a cam 56 having a downwardly facingsloping cam surface 58. The upper drive arm 50 is of generally similarconstruction as lower drive arm 48 and also comprises a central ringportion 60 defining a circular opening greater than the diagonaldimension of retaining shaft 38. Ring portion 60 carries a cam 62 havinga downwardly projecting sloping cam surface 64. The primary differencebetween upper drive arm 50 and lower drive arm 48 is that the dimensionsof the cams 55ts2, measured axially of the center line of the connectorbody, are such as to position the cam surfaces 58, 64 so that they aresubstantially equally spaced from the front wall 26. Thus, the cam 62 islonger than cam 56, and, in fact, overlaps the central ring portion 54of the lower drive arm 43.

The spacer 52 is mounted on retaining shaft 3%, separates the upper andlower drive arms 48, 50 and is generally cylindrical, but has a centralopening 66 resembling an oval with two opposing straight sides (see FIG.4). The straight sides of the opening 66 engage opposite surfaces of thesquare retaining shaft 38 so that the spacer is restrained fromrotational movement relative to the shaft. The curved ends of the ovalopening 66, however, are spaced from the sides of the retaining shaft38.

Positioned within the circular opening of lower drive arm ring portion54 and around retaining shaft 38 is a coiled torsion lower drive spring68. The end 63a of lower drive spring 68 is disposed near boss 34 andbent radially outwardly to extend through a suitable radial openingwithin ring portion 54- of the lower drive arm The other end 68b of thelower drive spring 68 is bent axially and extends along the retainingshaft 38 and into one curved end of the oval opening an in spacer 52.The lower drive spring 68 is conditioned and mounted so as to tend tomaintain the lower drive arm and its cam 56 in the position illustratedin FIGS. 2 and 3.

An upper torsion drive spring '76, somewhat similar to spring 68, ispositioned between the rpper drive arm ring portion tit and the squareretaining shaft 38. Spring lib is provided with one end 'l'tla which isbent axially along retaining shaft 38 and extends into the other curvedend of the oval opening in spacer 52. The other end 705 of upper drivespring 7t? is bent radially outwardly to extend into a radial opening'72 in the ring portion an. Upper drive spring 7% is conditioned andmounted so as to tend to maintain the upper drive arm and its cam 62 inthe position illustrated in FIGS. 2 and 3.

Operation of the automatically interlocking connector of this inventionmay be best understood by reference to FIGS. 3, 4 and 5. In FIG. 3, theaxially advancing male contact blades 13 projecting from connector capare shown as initially engaging the cam surfaces 58, 64, respectively,of the cams of lower and upper drive arms 48 and 59. It should be notedthat a corner 19 of each con tact blade 18 opposite the corner on itslug 36 engages a cam surface. As the contact blades are inserted furtherthrough slots 28, their increased engagement with the cam surfacesgenerates a rotational component of force on the cams and forces thelower drive arm 48 and the upper drive arm 59 to rotate substantiallysimultaneously in a counterclockwise direction relative to the advancingcap against the increasing resistance exerted by the drive springs.Spacer 52 remains fixed to the retaining shaft 38 and may be operativelyconsidered an extension of-the retaining shaft.

FIG. 4 is a somewhat schematic view looking down relative to FIG. 3, andillustrates the manner in which the lower and upper drive arms arecammed as the contact blades 18 are axially advanced. As the upper andlower drive arms are forced to rotate, they tension the coiled springs,and the springs exert greater and greater resistance counter forces.Sufiicient axial advancement of cap it) eventually allows the shoulder32 on each of the contact blades 13 to clear the inner surfac ofthefront wall 26 and, at about the same time, corners 19 of blades 18that have ridden on the cam surfaces pass the curved portions ofsurfaces 58 and 64 and engage straight portions 58 and 6 thereof,respectively. As the shoulders 32 have cleared the inner surface offront wall 26, the cap it) is free to rotate clockwise relative to itsdirection of advancement. The drive arms are driven by the individuallytensioned coil springs, which release their stored energy, so as torotate the blades 18 and drive their shoulders .32

behind front wall 26, locking the cap and body together. This positionis illustrated in FIG. 5.

In order to separate cap 10 from body 12, it is merely necessary torotate the cap relative to the body in the opposite direction to thatwhich effects interlocking. This causes a corner 19 of each of blades 18to force its associated straight portion of the cams to rotate.Continued rotation moves the cams back into their position wherein theyare axially aligned with slots 18, as shown in FIG. 4, allowing theblades 18, 13' to be withdrawn through slots 28 by a slight axiallyseparating pull apart, after which the corners 19 pass onto cam surfaces53 and 64 and the latter cam the contact blades 18 axially away frombody 12.

It will now be seen that the invention provides an electrical connectorbody having therein a pair of cams which are positioned to engage theadvancing male contact blades of an electrical connector cap and effectinitial automatic interlocking. It should also be noted that the camsproduce powered ejection of the contact blades on disconnection of thecap and body. The cam surfaces of the cams are integral portions ofrespective drive arms which are independently mounted on a singleretaining shaft and are powered by separate springs, and accordingly,

misalignment of an inserted contact blade has no adverse affect on theoperation of the device for the cams operate independently. By reason ofthis invention, automatic interlocking of electrical connector parts canbe easily achieved. The device of the invention is simple inconstruction having few moving elements.

It will be apparent that a number of variations and modifications may bemade in this invention, without departing from its spirit and scope. Forexample, the inventio-n, has been illustrated and described as embodiedwithin a cylindrical connector body. However, this is not a limitingfeature as the device may be built into any type of suitable connectorpart, for example, into a boxlike electrical receptacle, asdistinguished from a cylindrical connector body. Furthermore, thematerials of which the invention are constructed may be varied. It isimportant, of course, that the male contact blades not be shortcircuited and for this reason, it is desirable to construct the upperand lower drive arms of a suitable dielectric material, such as anysuitable plastic. Metallic carns could be used, however, if suitableinsulating means is employed. Other variations and modifications of theinvention will be apparent to those skilled in the art. Accordingly, itis to be understood that the invention is not limited to theconstruction specifically described herein and that it is limited onlyby the scope of the following claims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

l. An interlocking electrical connector comprising: a body of electricalinsulating material; a front wall on said body defining a plurality ofcircumfercntially aligned spaced arcuate openings therethrough; a raisedcentral boss supported by said front wall within said body and extendingon an axis falling substantially intermediate said openings; a retainingshaft supported at a first end by said boss and extending on an axisnormal to said front wall from the common center of a circle on whichsaid openings are disposed, the second end of said shaft spaced from theinner end of said boss and including an enlarged head; a first bladepositioning means adjacent the inner end of said boss, mounted forcontrolled partial rotation about said shaft; a second blade positioningmeans adjacent said head, mounted for controlled partial rotation aboutsaid shaft independent of said first positioning means; each of saidfirst and second blade positioning means including an inclined camsurface positioned to intercept an interlocking male contact bladeinserted in an associated one of said openings and initially be rotatedthereby but thereafter to rotate said blade, each of said cam surfacesbeing of a length such that said blade leaves the inclined portion ofsaid cam surface prior to reaching its position of maximum insertioninto said body; a first coiled torsion spring intermediate said firstblade positioning means and said shaft and having a first end secured tosaid first blade positioning means; a second coiled torsion springintermediate said second blade positioning means and said shaft andhaving a first end secured to said second blade positioning means; andsecuring means interconnecting said shaft and the second ends of each ofsaid first and second springs; said springs arranged to bias theinserted blades rotationally into an interlocking position relative tosaid front wall on the blades reaching a predetermined amount ofinsertion.

2. The connector of claim 1 wherein said securing means comprises aspacer atfixed to said shaft between said first and second positioningmeans.

3. The connector of claim 2 wherein said shaft has at least one flatside and wherein said spacer defines an opening therein having at leastone fiat side mating non-rotatably with said shaft.

References Cited by the Examiner UNITED STATES PATENTS 2,635,131 4/1953Greatbatch 339-41 X 3,066,276 11/1962 Hubbell et al 339-189 FOREIGNPATENTS 705,485 4/1941 Germany.

ALBERT H. KAMPE, Primary Examiner.

JOSEPH D. SEERS, Examiner.

1. AN INTERLOCKING ELECTRICAL CONNECTOR COMPRISING; A BODY OF ELECTRICALINSULATING MATERIAL; A FRONT WALL ON SAID BODY DEFINING A PLURALITY OFCIRCUMFERENTIALLY ALIGNED SPACED ARCUATE OPENINGS THERETHROUGH; A RAISEDCENTRAL BOSS SUPPORTED BY SAID FRONT WALL WITHIN SAID BODY AND EXTENDINGON AN AXIS FALLING SUBSTANTIALLY INTERMEDIATE SAID OPENINGS; A RETAININGSHAFT SUPPORTED AT A FIRST END BY SAID BOSS AND EXTENDING ON AN AXISNORMAL TO SAID FRONT WALL FROM THE COMMON CENTER OF A CIRCLE ON WHICHSAID OPENINGS ARE DISPOSED, THE SECOND END OF SAID SHAFT SPACED FROM THEINNER END OF SAID BOSS AND INCLUDING AN ENLARGED HEAD; A FIRST BLADEPOSITIONING MEANS ADJACENT THE INNER END OF SAID BOSS, MOUNTED FORCONTROLLED PARTIAL ROTATION ABOUT SAID SHAFT; A SECOND BLADE POSITIONINGMEANS ADJACENT SAID HEAD, MOUNTED FOR CONTROLLED PARTIAL ROTATION ABOUTSAID SHAFT INDEPENDENT OF SAID FIRST POSITIONING MEANS; EACH OF SAIDFIRST AND SECOND BLADE POSITIONING MEANS INCLUDING AN INCLINED CAMSURFACE POSITIONED TO IN TERCEPT AN INTERLOCKING MALE CONTACT BLADEINSERTED IN AN ASSOCIATED ONE OF SAID OPENINGS AND INITIALLY BE ROTATEDTHEREBY BUT THEREAFTER TO ROTATE SAID BLADE, EACH OF SAID CAM SURFACESBEING OF A LENGTH SUCH THAT SAID BLADE LEAVES THE INCLINED PORTION OFSAID CAM SURFACE PRIOR TO REACHING ITS POSITION OF MAXIMUM INSERTIONINTO SAID BODY; A FIRST COILED TORSION SPRING INTERMEDIATE SAID FIRSTBLADE POSITIONING MEANS AND SAID SHAFT AND HAVING A FIRST END SECURED TOSAID FIRST BLADE POSITIONING MEANS; A SECOND COILED TORSION SPRINGINTERMEDIATE SAID SECOND BLADE POSITIONING MEANS AND SAID SHAFT ANDHAVING A FIRST END SECURED TO SAID SECOND BLADE POSITIONING MEANS; ANDSECURING MEANS INTERCONNECTING SAID SHAFT AND THE SECOND ENDS OF EACH OFSAID FIRST AND SECOND SPRINGS; SAID SPRING ARRANGED TO BIAS THE INSERTEDBLADES ROTATIONALLY INTO AN INTERLOCKING POSITION RELATIVE TO SAID FRONTWALL ON THE BLADES REACHING A PREDETERMINED AMOUNT OF INSERTION.